scholarly journals Simple Method for Calculating the Flow Rate in a Cylindrical Tube of Arbitrary Length over a Whole Flow Regime

2020 ◽  
Vol 63 (7) ◽  
pp. 373-380
Author(s):  
Hajime YOSHIDA ◽  
Yoshinori TAKEI ◽  
Kenta ARAI
Keyword(s):  
Flow Regime ◽  
Flow Rate ◽  
Cylindrical Tube ◽  
Simple Method ◽  
Arbitrary Length

Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

UNSTEADY MODEL OF TRANSPORTATION OF JEFFREY-FLUID BY PERISTALSIS

2010 ◽  
Vol 03 (04) ◽  
pp. 473-491 ◽  
Author(s):  
S. K. PANDEY ◽  
DHARMENDRA TRIPATHI
Keyword(s):  
Relaxation Time ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Cylindrical Tube ◽  
Maximum Flow ◽  
Mechanical Efficiency ◽  
Volume Flow ◽  
Jeffrey Fluid ◽  
Retardation Time ◽  
Circular Cylindrical Tube

The investigation is to explore the transportation of a viscoelastic fluid by peristalsis in a channel as well as in a circular cylindrical tube by considering Jeffrey-model. In order to apply the model to the swallowing of food-bolus through the oesophagus, the wave equation assumed to propagate along the walls is such that the walls contract in the transverse/radial direction and relax but do not expand further. Solutions have been presented in the closed form by using small Reynolds number and long wavelength approximations. The expressions of pressure gradient, volume flow rate and average volume flow rate have been derived. It is revealed on the basis of computational investigation that for a fixed flow rate, pressure decreases when the ratio of relaxation time to retardation time is increased. In both the channel and tubular flows, the pressure decreases on increasing the ratio of relaxation time to retardation time if the averaged flow rate is less than the maximum flow rate. It is also revealed that the maximum tubular flow rate is higher than that of the channel-flow. It is further found through the theoretical analysis that mechanical efficiency, reflux and local wall shear stress remain unaffected by viscoelastic property of the fluid modelled as Jeffrey-fluid.

Preparation and Characterization of Poly(Methyl Methacrylate) (PMMA) Fibers by Electrospinning

2019 ◽  
Vol 811 ◽  
pp. 163-169 ◽  
Author(s):  
Ervin Tri Suryandari ◽  
Muhammad Ali Zulfikar ◽  
Rino R. Mukti ◽  
Muhamad Nasir
Keyword(s):  
Methyl Methacrylate ◽  
Flow Rate ◽  
Supply Voltage ◽  
High Surface ◽  
Polymer Concentration ◽  
Diameter Distribution ◽  
Solution Flow Rate ◽  
Simple Method ◽  
Poly Methyl Methacrylate ◽  
Small Pore

Fibers are materials with advantageous properties such as lightweight material properties, has small pore size, and has high surface area, porosity,and permeability. An easy and simple method to prepare fibers is electrospinning. Using this method poly(methyl methacrylate) (PMMA) fibers were prepared. Several parameters include polymer concentration, solution flow rate, the distance of the nozzle tip to the collector, and the applied voltage were investigated to control the morphology, structure, and diameter of PMMA fibers. The Optimal electrospinning conditions for PMMA fibers production were a PMMA concentration is 8% (w/v), a power supply voltage is 20 kV, a distance of the tip of the nozzle to the ground collector is 15 cm, and a flow rate is 0.004 mL/min. The diameter distribution and morphology of the fibers were determined and characterized by Optical Microscopy and Scanning Electron Microscope (SEM), which showed that the produced fiber had an average diameter of 1.4925 µm, the contact angle of fiber PMMA is 125.307o and the spreading time of fibers PMMA is about 360 minutes

A simple method for perfusion fixation of avian liver for electron microscopy

1981 ◽  
Vol 59 (6) ◽  
pp. 1179-1183 ◽  
Author(s):  
M. K. Bhatnagar ◽  
L. L. David ◽  
Olga Vrablic ◽  
A. Therien ◽  
Andre Blouin
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Flow Rate ◽  
Phosphate Buffer ◽  
Perfusion Pressure ◽  
Maximum Flow ◽  
Compressed Air ◽  
Simple Method ◽  
Dense Matrices ◽  
Perfusion Fixation

A simple method and apparatus are described for perfusion fixation of avian liver for electron microscopy. A constant perfusion pressure is maintained at or below a fixed value with the use of a compressed air cylinder and without the use of automatic devices. A hyperosmotic (580–600 mosm) fixative solution containing 4% glutaraldehyde, 0.0005 M CaCl2, and 0.0005 M MgCl2 in 0.05 M phosphate buffer (pH 7.4, buffer osmolality 122 mosm) produced consistent fixation without swelling or undue shrinkage. The cytoplasmic organelles were well preserved; notably, the mitochondria had electron-dense matrices and well-defined cristae. A pressure of 60 mmHg (1 mmHg = 133.322 Pa) maintained by compressed air permits a minimum to maximum flow rate of 14–19 mL∙min−1∙kg body weight−1, and optimum preservations of the architecture of sinusoids.

scholarly journals Non-equilibrium dynamics of dense gas under tight confinement

2016 ◽  
Vol 794 ◽  
pp. 252-266 ◽  
Author(s):  
Lei Wu ◽  
Haihu Liu ◽  
Jason M. Reese ◽  
Yonghao Zhang
Keyword(s):  
Boltzmann Equation ◽  
Flow Regime ◽  
Mass Flow Rate ◽  
Knudsen Number ◽  
Mass Flow ◽  
Flow Rate ◽  
Transitional Flow ◽  
Molecular Flow ◽  
Parallel Plates ◽  
The Boltzmann Equation

The force-driven Poiseuille flow of dense gases between two parallel plates is investigated through the numerical solution of the generalized Enskog equation for two-dimensional hard discs. We focus on the competing effects of the mean free path ${\it\lambda}$, the channel width $L$ and the disc diameter ${\it\sigma}$. For elastic collisions between hard discs, the normalized mass flow rate in the hydrodynamic limit increases with $L/{\it\sigma}$ for a fixed Knudsen number (defined as $Kn={\it\lambda}/L$), but is always smaller than that predicted by the Boltzmann equation. Also, for a fixed $L/{\it\sigma}$, the mass flow rate in the hydrodynamic flow regime is not a monotonically decreasing function of $Kn$ but has a maximum when the solid fraction is approximately 0.3. Under ultra-tight confinement, the famous Knudsen minimum disappears, and the mass flow rate increases with $Kn$, and is larger than that predicted by the Boltzmann equation in the free-molecular flow regime; for a fixed $Kn$, the smaller $L/{\it\sigma}$ is, the larger the mass flow rate. In the transitional flow regime, however, the variation of the mass flow rate with $L/{\it\sigma}$ is not monotonic for a fixed $Kn$: the minimum mass flow rate occurs at $L/{\it\sigma}\approx 2{-}3$. For inelastic collisions, the energy dissipation between the hard discs always enhances the mass flow rate. Anomalous slip velocity is also found, which decreases with increasing Knudsen number. The mechanism for these exotic behaviours is analysed.

Air Sparging for Mixing Non-Newtonian Slurries

2010 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Carl W. Enderlin ◽  
S. Tzemos
Keyword(s):  
Flow Regime ◽  
Flow Rate ◽  
Air Flow ◽  
Newtonian Fluids ◽  
Air Sparging ◽  
Air Bubbles ◽  
Air Flow Rate ◽  
Primary Flow ◽  
Zone Of Influence ◽  
Made In

The mechanics of air sparger systems have been primarily investigated for aqueous-based Newtonian fluids. Tilton et al. (1982) [1] describes the fluid mechanics of air sparging systems in non-Newtonian fluids as having two primary flow regions. A center region surrounding the sparger, referred to as the region of bubbles (ROB), contains upward flow due to the buoyant driving force of the rising bubbles. In an annular region, outside the ROB, referred to as the zone of influence (ZOI), the fluid flow is reversed and is opposed to the direction of bubble rise. Outside the ZOI the fluid is unaffected by the air sparger system. The flow regime in the ROB is often turbulent, and the flow regime in the ZOI is laminar; the flow regime outside the ZOI is quiescent. Tests conducted with shear thinning non-Newtonian fluid in a 34-in. diameter tank showed that the ROB forms an approximately inverted cone that is the envelop of the bubble trajectories. The depth to which the air bubbles reach below the sparger nozzle is a linear function of the air-flow rate. The recirculation time through the ZOI was found to vary proportionally with the inverse square of the sparging air-flow rate. Visual observations of the ROB were made in both water and Carbopol®. The bubbles released from the sparge tube in Carbopol® were larger than those in water.

Flow-driven morphology control in the cobalt–oxalate system

CrystEngComm ◽  
2016 ◽  
Vol 18 (12) ◽  
pp. 2057-2064 ◽  
Author(s):  
Eszter Tóth–Szeles ◽  
Gábor Schuszter ◽  
Ágota Tóth ◽  
Zoltán Kónya ◽  
Dezső Horváth
Keyword(s):  
Fluid Flow ◽  
Density Gradient ◽  
Flow Rate ◽  
Morphology Control ◽  
Simple Method ◽  
System P ◽  
Cobalt Oxalate

The presence of fluid flow by maintaining the density gradient and controlling the flow rate provides a simple method to modify the microstructure of cobalt oxalate.

scholarly journals A Mathematical Model for the Flow of a Casson Fluid due to Metachronal Beating of Cilia in a Tube

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
A. M. Siddiqui ◽  
A. A. Farooq ◽  
M. A. Rana
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Pressure Rise ◽  
Cylindrical Tube ◽  
Casson Fluid ◽  
Volume Flow ◽  
System Of Nonlinear Equations ◽  
Dimensional System ◽  
Axial Pressure Gradient

A mathematical model is developed to study the transport mechanism of a Casson fluid flow inspired by the metachronal coordination between the beating cilia in a cylindrical tube. A two-dimensional system of nonlinear equations governing the flow problem is formulated by using axisymmetric cylindrical coordinates and then simplified by employing the long wavelength and low Reynolds number assumptions. Exact solutions are derived for the velocity components, the axial pressure gradient, and the stream function. However, the expressions for the pressure rise and the volume flow rate are evaluated numerically. The features of the flow characteristics such as pumping and trapping are illustrated and discussed with the help of graphs. It is observed that the volume flow rate is influenced significantly by the width of plug flow regionHpas well as the cilia length parameterε. The analysis is also applied and compared with the estimated value of the volume flow rate of epididymal fluid in the ductus efferentes of the human male reproductive tract.

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